Lung Cancer in "Never-Smokers"

If taken as a separate disease, lung cancer in those who have never smoked in their lives would be the sixth largest cancer killer in the world.

Overall, 15% of new lung cancer diagnoses are in people who have never smoked (defined as less than 100 cigarettes over a lifetime). Another 50% are in people who have quit smoking years ago. Of course, the best way to reduce your risk of lung cancer is to never start smoking and to quitif you do smoke. However, if everyone quit smoking today, lung cancer would still be a public health issue.

In the United States, nearly 10% of lung cancers in men and nearly 20% of lung cancers in womenoccur in those who have never smoked. 17,000 "never-smoker" American women die from lung cancer each year. This is over four times the number of cervical cancer deaths. There has been a significant increase in lung cancer in non-smoking, middle-aged women in recent years.

The most common causes of lung cancer in never-smokers is exposure to radonand one's own genetic makeup. Radon is a natural radioactive gas that you can't see, smell or taste. Radon can seep into houses (usually in the basement) from naturally occurring uranium in the soil.

Lung cancer in never-smokers differs in at least two major respects from lung cancer in smokers:

1. When examined under a microscope, certain types of cancer cells are more commonly found in cancerous tissues of never-smokers than in lung cancers present in smokers.

2. Never-smokers more often have mutations in the gene for epidermal growth factor receptor (EGFR). These mutations foster the harmful, uncontrolled growth of cells that is characteristic of cancer.

Diagnosis Often Comes Late

Lung cancer in both smokers and never-smokers is usually first detected in advanced stages of the disease because the most common symptoms -- cough, chest pain, and shortness of breath -- are not particularly specific. Diagnosis can be delayed even further in never-smokers because doctors may not consider the possibility that they might have lung cancer. Unfortunately, survival rates appear equally dismal in smokers and in never-smokers.